Surgical pouches have been developed for use in laparoscopic surgery to remove tissue specimens from the abdominal cavity. The purpose of the pouch is to keep the tissue specimen intact as it is removed through the trocar site in the abdominal wall. Typically, these pouches have been made from a polymeric film. Usually, these devices employ a closure means at the open end or mouth of the pouch to prevent spillage of tissue or fluids into the abdomen. For example, the closure means has been described in the prior art as a thread or suture which passes around the mouth of the pouch through a channel formed by a folded edge which is heat sealed to the side of the pouch. Also, the closure means has been described as a wire arranged in a single or double loop.
Although the surgical pouches of the prior art have been developed for the removal of the tissue from the abdomen through an incision at a trocar site, there has been a problem in the placement of the tissue into the pouch prior to the closure and removal of the pouch from the abdominal cavity, In the prior art devices, the mouth of the pouch does not remain wide open and the lack of stability at the mouth makes it difficult to accomplish the desired positioning of the pouch inside the body cavity. Because of these factors, it is necessary for the surgeon to use a first grasper to hold the mouth of the pouch and a second grasper to attempt to place the tissue into the pouch. The need for the additional grasper may require the insertion of an extra trocar tube into the abdominal wall.
Another problem associated with the devices of the prior art is inability of the closed pouch to be opened or reopened inside the body cavity. In the prior art devices which employ a thread or wire as the closure or cinching mechanism, once the pouch is closed about the tissue specimen, the pouch cannot be opened until the pouch is removed from the body cavity. This problem arises because of the difficulty in loosening the knot at the base of the wire loop and in removing the wire from the channel around the mouth of the pouch.
Examples of surgical retrieval devices with drawstrings for closing the pouches are disclosed in U.S. Pat. Nos. 5,037,379 and 5,143,082. Clayman et al U.S. Pat. No. 5,037,379 discloses a surgical tissue bag including a drawstring for drawing the open end of the bag closed and for pulling the closed open end of the bag from a body cavity through a trocar sheath. Kindberg et al U.S. Pat. No. 5,143,082 discloses a surgical device for enclosing an internal body organ or tissue which includes a filamentary strand extending through a tubular sleeve and formed into a noose about the open end of a surgical bag. The noose is secured by a knot which allows the strand to be pulled into the tubular sleeve to close the surgical bag and which prevents the noose from loosening when engaged about an internal body organ or tissue. Neither of these examples discloses any mechanism to enhance the stability of the drawstrings.
Wetter et al U.S. Pat. No. 5,190,555 discloses another example of an endoscopic tissue retrieval device for the collection and removal of internal body parts including a drawstring used for closing and opening a flexible funnel-shaped sack. The device includes a tubular member of relatively rigid material provided with a longitudinal slot in which a side portion of the flexible sack is secured. No mention is made of any arrangement to enhance the stability of the drawstring.
Rydell U.S. Pat. No. 5,163,942 discloses a surgical grasping instrument including a belt which forms an extendable and retractable grasping loop for laparoscopic procedures. The instrument is used to rotate an internal organ or tissue about the longitudinal axis of the instrument or about an axis transverse to the longitudinal axis. The Rydell instrument is used to grasp and manipulate internal organs, e.g., the gallbladder, during cauterization, but no pouch is provided to enclose and retrieve the tissue.
Nakao et al U.S. Pat. No. 5,190,542 discloses a surgical instrument for use in snare cauterization including a flexible web member which forms a capture pocket and a flexible cauterization loop at the mouth of the pocket. The cauterization loop is extendable and retractable into a sheath member to open and close the flexible web member. The sheath member is retractable through an endoscope to remove the cauterized tissue. A flexible auxiliary loop of synthetic resin or polymeric material is disclosed, but no provision is made to stabilize the cauterization loop.
An object of the present invention is to provide an improved tissue retrieval instrument for use in endoscopic surgery.
Another object of the invention is to provide a surgical instrument for retrieving internal body tissue having a collapsible pouch and a cinching mechanism which enhances the stability of the open end of the pouch when expanded inside a body cavity to facilitate the tissue placement in the pouch.
A further object of the invention is to provide a tissue retrieval instrument including a collapsible pouch and a cinching mechanism which enables the pouch to be reopened inside the body cavity to receive additional pieces of tissue.
It is another object of the invention to provide an endoscopic instrument for retrieving internal body tissue including a collapsible pouch and a cinching mechanism in the form of a belt with an oblong or rectangular cross section to enhance the stability of the open end of the pouch in its expanded configuration.
Another object of the invention is to provide a surgical instrument for retrieving internal body tissue including a collapsible pouch, a belt formed into a loop attached about the open end of the pouch, and a ratchet mechanism for advancing and retracting the belt to expand and contract the open end of the pouch.
It is a further object of the invention to provide an endoscopic instrument for retrieving internal body tissue including a collapsible pouch which is tapered and elongated to align the tissue in a desired orientation in the pouch to facilitate the passage of the tissue through a trocar site.